Process for improving flavor and taste of soybean oil



United States Patent ice a 3,169,981 PROCESS FOR IMPROVING FLAVOR ANDTASTE OF SOYBEAN OIL Tsutomu Kuwata, Tokyo, Shizuo Takumi,Kamalrura-shi, Kanagawa-ken, and Tosliio Hashimoto, Yokohama-shi,Kanagawa-ken, Japan, assignors to Nikki Kagaku giabushiki Kaisha, Tokyo,Japan, a corporation of apan Y a 1 No Drawing. Filed July 31, 1962, Ser.No. 213,617 Claims priority, application Japan, Dec. 12, 1961,

36/ 44,764 1 Claim. (Cl. 260-409) This invention relates to a processfor improving flavor and taste of soybean oil, more particularly aprocess for improving flavor and taste of soybean oil by selectivelyhydrogenating the oil in the presence of a copper chromium manganeseoxide catalyst.

It has been well known that cottonseed oil is used for salad oil orother cooking oil as an excellent quality. While soybean oil may be usedas salad or cooking oil, it has a peculiar odor and has an unfavorabledefect of deteriorating its flavor and taste during storage, so that thequality of soybean oil is said to be much inferior to that of cottonseedoil.

The inventors have found that the defects of soybean oil abovementionedcan be much improved by the partial hydrogenation of the oil by thecopper chromium manganese oxide catalyst. The partial hydrogenationconditions are as follows:

Reaction temperature: ISO-220 C.

Reaction pressure: Atmospheric pressure Reaction time: 30-90 minutesAmount of catalyst to the oil: 0.1-0.2%

Iodine number of hydrogenated oil: 110-115 Percentage of linolenic acidin the hydrogenated oil: 0

The results of the inventors analysis on the compositions of soybean oiland cottonseed oil are as follows:

Referring, now, to the following examples the present invention will beexplained in detail:

Example 1 Into an aqueous solution prepared by dissolving 126.1 g. (0.5mole) of ammonium bichromate in 500 cc. of

water, 150 cc. of 28% ammonia water was added and into the solution,asolution prepared by dissolving in 500 cc; of water 241.6 g. (1.0 mole)of crystalline copper nitrate or 249.7 g. (1.0 mole) of crystallinecopper sulfate and 28.7 g. (0.1 mole) of crystalline manganese nitrateor 27.7 g. (0.1 mole) of crystalline manganese sulfate was addeddropwise with stirring'to for-m a precipitate, which was Washed withwater, dried, ground and roasted at 350 C. to give a catalyst.

3,169,981 Patented Feb. 16, 1965 Example 2 i 100 g. of refined soybeanoilas in Example 1 was mixed with 0.2 g. of the catalyst prepared by thesame method as in the case of Example 1 and hydrogenated for /2 hour at200 C. in atmospheric pressure.

salad oil having an iodine number of 110.was obtained and the oil passedthe cooling test.

' Example 3 e tions as in the case of Example 2. In these cases thehydrogenations advanced too much, which resulted in decreasing theiodine numbers to 80.56 and the treated oils did not stand the coolingtest. Namely, it is clear that the suitable amount of the catalyst forthe object of this invention should be 0.1-0.2%.

Example 4 The results of investigating the changes in the iodine numberand the compositions of soybean oil caused by the hydrogenation were asfollows:

During the hydrogenation of 100 g. of refined soybean oil in thepresence of 0.2 g. of the catalyst (Example 1) in atmospheric pressureof hydrogen at a temperature of 200 C., at a hydrogen flow of 1 L/min.and at anagitation of 850 rpm, samples were withdrawn at 0, 7, 14 and 20min. after beginning hydrogenation and the iodine numbers, percentagesof saturated acids, monoenes,

dienes, and trienes in the samples were determined. The

results were as follows:

Time of Iodine Satd. Mono- Dienes Trienes hydro- Appearance num- Acidsenes (per- (pergenation ber (per- (percent) cent) 5 (min) cent) cent) 0Li uid at room 219. 5 19. 2 21. 5 51. 8 7. 5

If the above results are plotted taking the iodine number on an ordinateand triene on an abscissa, they show a linear relation and the linecrosses with the ordinate at about 116, which shows that the content oftrienes becomes 0 when the iodine number is about 115.

In addition, the determination of dienes and trienes in the samples'weremade by using aultraviolet spectrophotometer and the amounts ofsaturated acids and mono- Ofiicial and Tentative Methods of theA.O.C.S., Cd 7-58 (1959). Beckman D.U. type spectrophotometer was usedand the length of the cell was 1 cm. 7

Further, in a selective hydrogenation process for fats and fatty oilsdisclosed in the Japanese Patent No. 244,354, esters or fats and fattyoils containing unsaturated acids higher than linolic acid arehydrogenated in atmospheric pressure of hydrogen or lower than 10pressure of hydrogen by using a copper chromium manganese oxidecatalyst, whereby all of unsaturated fatty acids higher than linolicacid are hydrogenated into oleic acid. By an example in which theprocess of the above patent is Soybean r g. of refined soybean oil wasmixed with 0.5 of the catalyst and hydrogenated under the same condieneswere determined by the calculation formulas in.

applied to soybean oil (Shizuo Takumi, Yukagaku, vol. 8, No. 6, 253459),when 100 g. of refined soybean oil having the iodine number of 128.01 ishydrogenated for 3 hours at 200 C. with the addition of 2 g. of a copperchromium manganese oxide catalyst, the iodine number is reduced to72.14. The invention of the present application, however, different fromthe above process that in this hydrogenation process, all of thelinolenic acid is hydrogenated to linolic acid and the hydrogenation oflinolic acid to oleic acid is suppressed by using copper chromiummanganese oxide catalyst.

We claim:

A process for improving'flavor and taste of soybean oil which compriseshydrogenating refined soybean oil in the presence of a copper chromiummanganese oxide 15 5 ber of the soybean oil to 110-115, and to reducethe content of lineolenic acid to zero.

References Cited in the file of this patent UNITED STATES PATENTS1,844,857 Larson Feb. 9, 1932 2,302,994 Gwynn Nov. 24, 1942 FOREIGNPATENTS 670,906 Great Britain Apr. 30, 1952

